Uncured articles with improved shelf-life

ABSTRACT

Disclosed are formaldehyde-free, thermally-curable, alkaline, aqueous binder compositions. Also disclosed are compositions comprising formaldehyde-free, thermally-curable binder compositions, as described herein, applied to non-woven fibers. Uses of the disclosed binder compositions as binders for non-woven fibers are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a U.S. national counterpart application ofInternational Application Serial No. PCT/US2015/014786, filed Feb. 6,2015, under 35 U.S.C. § 371, which claims priority under 35 U.S.C.§119(e) to U.S. Provisional Application Serial No. 61/937,110, filed Feb.7, 2014, the disclosures of which are hereby incorporated herein byreference.

TECHNICAL FIELD

This invention relates to binders and binder technology applicable inthe preparation of compositions that include non-woven fibers. Moreparticularly, the present invention relates to uncured mineral wool,i.e., uncured glass wool (fiberglass) and/or uncured stone wool,products (articles) prepared with formaldehyde-free binders that arecured (e.g., by molding) in a secondary step after the correspondinguncured products are collected.

BACKGROUND

So called “shipout uncured” and “plant uncured” fiberglass insulation ismanufactured with an uncured, thermosetting binder. The resultinguncured insulation products are collected, packaged into rolls, bagged,and sealed in plastic bags. At various times thereafter, the baggedinsulation material is i) transported to, ii) stored at, and iii)ultimately processed via a distinct separate manufacturing sequence by,a customer to yield a finished part. This manufacturing sequenceincludes heat curing of the binder. The time between collection of theuncured product and curing the binder can span several days to severalweeks. In the case of “shipout uncured” fiberglass insulation, theuncured product is transported to customers that require the product tohave a long shelf-life during ambient storage and transportationconditions. Ideally, “shipout uncured” fiberglass insulation has aminimum shelf-life of 2 to 4 weeks.

Standard binder for “shipout uncured” and “plant uncured” fiberglassinsulation has historically been based on phenol-formaldehyde (PF)binder chemistry. PF binders exhibit the disadvantage of formaldehydeemissions. Binders based on reducing sugar carbohydrates for curedproduct lines are known in the art. Due to an increasingly uncertainregulatory situation as it pertains to the use offormaldehyde-containing binders and/or formaldehyde-liberating products,there has been steadily increasing interest in, if not demand for, asustainable, formaldehyde-free binder based on carbohydrates for“shipout uncured” and “plant uncured” fiberglass insulation. Heretofore,the prior art has not described such a binder, or an equivalent bindercomposition, for such uncured fiberglass insulation products.

Initial trials aimed at discovering a carbohydrate-based binder foruncured fiberglass insulation product lines involved dextrose as thecarbohydrate source. The resulting uncured product rolls displayed majordisadvantages, which included the fact that: a) the dextrose-basedbinder crystallized out and caused poor loft and poor recovery whenunrolling the fiberglass rolls, b) the dextrose-based binder migrated tothe glass surface and segregated out into binder “islands,” whichislands were noticeable after curing/molding as a darkly-colored dottedpattern, c) due to binder migration, the inner part of the fiberglasslayer was depleted of binder whereas the outer pelt surface was binderrich, which depletion caused weakened integrity of the cured/moldedproduct whereas binder enrichment and crystallization on the peltsurface resulted in poor handling characteristics when molding (i.e.,binder rich areas tended to stick to the mold platens, which oftenresulted in the destruction of the molded part when removing it from theplaten), and d) when a permeable membrane (e.g., non-woven glass veil)was used, binder rich spots often bled through the veil upon molding.

OBJECTS OF THE INVENTION

One object of the present invention is to provide a carbohydrate-basedbinder that enables the manufacture of uncured fiberglass insulationproducts with good shelf-life during ambient transportation and storageconditions (e.g., in winter and summer; in northern and southernclimate).

Another object of the present invention is to provide acarbohydrate-based binder that does not significantly and/or noticeablymigrate within finished uncured fiberglass insulation products withconcomitant localized depletion of binder.

Another object of the present invention is to provide acarbohydrate-based binder that does not crystallize out in finisheduncured fiberglass insulation products and thereby form dotted patternstherein after cure.

Yet another object of the present invention is to provide acarbohydrate-based binder that does not significantly and/or noticeablymigrate within finished uncured fiberglass insulation products withconcomitant localized enrichment of binder.

SUMMARY

One aspect of the present invention provides a carbohydrate-based binderin accordance with claim 1; the dependent claims define alternativeand/or preferred embodiments.

In another illustrative aspect, the present invention provides acarbohydrate-based binder solution comprising a mixture ofcarbohydrates, an acid precursor derivable from an inorganic salt and/oran ammonium salt of one or more polycarboxylic acids, a source ofnitrogen, and optionally ammonia.

In another illustrative aspect, the present invention provides a binderbased on a mixture of carbohydrates that has a tendency to generatesupersaturated aqueous solutions of sugars that do not crystallize outwhile storing at ambient conditions over a time span of at least 3 days,preferably over a time span of longer than 2 weeks even when in contactwith fiberglass.

In another illustrative aspect, the present invention provides for acarbohydrate-based binder wherein the mixture of sugars in the binderhas a lower crystallization point than dextrose.

In another illustrative aspect, the present invention provides for acarbohydrate-based binder wherein the mixture of sugars is fructose anddextrose present in high fructose corn syrup (HFCS), which is used as acarbohydrate source.

In another illustrative aspect, the present invention provides for acarbohydrate-based binder which permits close control of the ratio ofmoisture to binder concentration in a fiberglass product.

In another illustrative aspect, the present invention provides for acarbohydrate-based binder where impurities may be added to mixtures offructose and dextrose (e.g., mixtures obtained by dissolving fructoseand dextrose or by inverting sucrose under known conditions to invertsugar). Such impurities may be dextrins and/or maltodextrins. Anotherform of impurities can be generated by heating tcarbohydrate solutionsto form some degradation products.

In another illustrative aspect, the present invention provides for acarbohydrate-based binder where various additives may be added toimprove binder performance and processability. Typical additives knownin the art include, but are not necessarily limited to, adhesionpromoters, coupling agents, silanes, amino-silanes, silicones,non-aqueous moisturizers, flame retardants, additives to preventself-heating upon curing, dedusting oils, polymeric additives (e.g.,styrene-maleic anhydride copolymers, acrylic copolymers), andcross-linkers (e.g., mono-, di-, and polyfunctional amines, epoxides,isocyanates, blocked isocyanates, hydroxyl-containing compounds, andcarboxy-containing compounds, as well as aldehyds and ketones.)

In another illustrative aspect, a method for treating fibers, includingnon-woven fibers, is enabled that includes contacting mineral fibers(e.g., glass fibers) with a thermally-curable, aqueous bindercomposition comprising a mixture of carbohydrates, an acid precursorderivable from an inorganic salt and/or an ammonium salt of one or morepolycarboxylic acids, a source of nitrogen, and optionally ammonia, asdescribed herein, and effecting removal of most of the water from thethermally-curable, aqueous binder composition in contact with mineralfibers.

In another illustrative aspect, a fiberglass product is described thatincludes a binder composition, as described herein, in contact withglass fibers, which product may be processed to form one of severaltypes of uncured fiberglass insulation, wherein the glass fibers arepresent in the range from about 80% to about 99% by weight.

Binder solutions used in accordance with the present invention may be“substantially formaldehyde free”, that is to say that they liberateless than 5 ppm formaldehyde as a result of drying and/or curing (orappropriate tests simulating drying and/or curing). Such bindersolutions are preferably “formaldehyde free”, that is the say theyliberate less than 1 ppm formaldehyde in such conditions.

Products in accordance with the present invention (for example, uncuredfiberglass insulation materials) may be “substantially formaldehydefree;” that is to say that they comprise less than 5 ppm or less thandetectable limits of free formaldehyde and/or consist of materials whichtogether comprise less than these amounts of free formaldehyde and/orrelease levels of formaldehyde in standardized tests adapted to simulatetheir ordinary use which allows them to be classified as having no orundetectable levels of formaldehyde release. Preferably, such productsrelease less than 10 μg/m³, more preferably less than 5 μg/m³, offormaldehyde during the period of 24-48 hours from the start of testingin accordance with ISO 16000.

Additional features of the present invention will become apparent tothose skilled in the art upon consideration of the following detaileddescription of illustrative embodiments exemplifying the best mode ofcarrying out the invention as presently perceived.

DETAILED DESCRIPTION

It has been found that binders according to the present invention mayhave at least equivalent and, in some instances, improved propertiescompared to, for example, the tri-ammonium citrate-dextrose system of WO2007/014236 and compared to, for example, the triammoniumphosphate-dextrose system of WO 2009/019235. WO 2007/014236 teachesbinder systems based, inter alia, on a combination of a carbohydrate(for example, a reducing sugar), ammonia and a polycarboxylic acid andsuggests that a Maillard type reaction may form the basis of the curingchemistry. WO 2009/019235 teaches binder systems based, inter alia, on acombination of a carbohydrate (for example, a reducing sugar), an acidprecursor derivable from an inorganic salt, and ammonia and suggeststhat a Maillard type reaction may form the basis of the curingchemistry. It would have been thought that inclusion of a mixture of atleast two carbohydrates would not have a significant effect on theproperties of the resulting uncured binder, particularly if thecarbohydrates are both reducing sugars. It is thus surprising that amixture of at least two carbohydrates (e.g., dextrose and fructose)should provide improved properties in an otherwise apparently similarbinder system.

Use of an acid precursor derivable from an inorganic salt may havesignificant advantages in terms of cost, availability and ease ofhandling. The acid precursor derivable from an inorganic salt of thebinder solution may comprise a species selected from the groupconsisting of sulfates, phosphates, nitrates and carbonates. Aparticular advantage can be achieved by use of one or more inorganicammonium salts, for example, an ammonium sulfate, an ammonium phosphateor an ammonium carbonate salt. An ammonium salt may provide the or partof the acid precursor and/or the or part of the source of nitrogenand/or the or part of a pH control system. An ammonium nitrate salt mayalso work; however, ammonium nitrate may oxidise aldehyde groups of thecarbohydrate (for example, aldehyde groups in dextrose) and/or requireprecautions to avoid explosions.

Ammonium sulfate is particularly advantageous but ammonium phosphate maybe used in addition to or instead of ammonium sulfate Ammonium phosphatemay be monoammonium phosphate, diammonium phosphate or triammoniumphosphate; it may be an ammonium hydrogen phosphate. An ammoniumcarbonate, alone or in combination with the other materials disclosedherein, may also provide good results. The ammonium carbonate may be anammonium bicarbonate.

The acid precursor, particularly when this consists essentially ofinorganic ammonium salt(s), may make up at least 5%, preferably at least7%, more preferably at least 9% by dry weight of the uncured bindersolution; and/or less than 25% or 20%, preferably less than 18%, morepreferably less than 16% by dry weight of the uncured binder solution.

The term “consist or consisting essentially of” is intended to limit thescope of a claim to the specified materials or steps and those that donot materially affect the basic and novel characteristic(s) of theclaimed invention.

The acid may comprise: a sulfuric acid, a phosphoric acid, a nitric acidor a weak acid.

The binder may comprise between 5% and 25%, preferably 10% to 20%, morepreferably 15% to 20% by dry weight of acid precursor (particularlywhere this is an inorganic ammonium salt) to total carbohydrate(particularly when this is a mixture of reducing sugars).

A carbohydrate-based binder comprising a mixture of carbohydrates, asdescribed herein, may alternatively or in addition contain an ammoniumsalt of one or more polycarboxylic acid components, where the salt ismonobasic or dibasic when the polycarboxylic acid component is adicarboxylic acid, or where the salt is monobasic, dibasic, or tribasicwhen the polycarboxylic acid component is a tricarboxylic acid, and soon and so forth.

As used herein, the term “ammonium” includes, but is not limited to,⁺NH₄, ⁺NH₃R¹ and ⁺NH₂R¹R², where R¹ and R² are each independentlyselected in ⁺NH₂R¹R², and where R¹ and R² are selected from alkyl,cycloalkyl, alkenyl, cycloalkenyl, heterocyclyl, aryl, and heteroaryl.

The term “alkyl” refers to a saturated monovalent chain of carbon atoms,which may be optionally branched; the term “cycloalkyl” refers to amonovalent chain of carbon atoms, a portion of which forms a ring; theterm “alkenyl” refers to an unsaturated monovalent chain of carbon atomsincluding at least one double bond, which may be optionally branched;the term “cycloalkenyl” refers to an unsaturated monovalent chain ofcarbon atoms, a portion of which forms a ring; the term “heterocyclyl”refers to a monovalent chain of carbon and heteroatoms, wherein theheteroatoms are selected from nitrogen, oxygen, and sulfur, a portion ofwhich, including at least one heteroatom, form a ring; the term “aryl”refers to an aromatic mono or polycyclic ring of carbon atoms, such asphenyl, naphthyl, and the like; and the term “heteroaryl” refers to anaromatic mono or polycyclic ring of carbon atoms and at least oneheteroatom selected from nitrogen, oxygen, and sulfur, such aspyridinyl, pyrimidinyl, indolyl, benzoxazolyl, and the like. It is to beunderstood that each of alkyl, cycloalkyl, alkenyl, cycloalkenyl, andheterocyclyl may be optionally substituted with independently selectedgroups such as alkyl, haloalkyl, hydroxyalkyl, aminoalkyl, carboxylicacid and derivatives thereof, including esters, amides, and nitriles,hydroxy, alkoxy, acyloxy, amino, alkyl and dialkylamino, acylamino,thio, and the like, and combinations thereof It is further to beunderstood that each of aryl and heteroaryl may be optionallysubstituted with one or more independently selected substituents, suchas halo, hydroxy, amino, alkyl or dialkylamino, alkoxy, alkylsulfonyl,cyano, nitro, and the like.

As used herein, the term “polycarboxylic acid” indicates a dicarboxylic,tricarboxylic, tetracarboxylic, pentacarboxylic, and like monomericpolycarboxylic acids, and anhydrides, and combinations thereof, as wellas polymeric polycarboxylic acids, anhydrides, copolymers, andcombinations thereof In one aspect, the polycarboxylic acid ammoniumsalt reactant is sufficiently non-volatile to maximize its ability toremain available for reaction with a mixture of carbohydrates in aMaillard reaction. In another aspect, the polycarboxylic acid ammoniumsalt reactant may be substituted with other chemical functional groups.

Illustratively, a monomeric polycarboxylic acid may be a dicarboxylicacid, including, but not limited to, unsaturated aliphatic dicarboxylicacids, saturated aliphatic dicarboxylic acids, aromatic dicarboxylicacids, unsaturated cyclic dicarboxylic acids, saturated cyclicdicarboxylic acids, hydroxy-substituted derivatives thereof, and thelike. Or, illustratively, the polycarboxylic acid(s) itself may be atricarboxylic acid, including, but not limited to, unsaturated aliphatictricarboxylic acids, saturated aliphatic tricarboxylic acids, aromatictricarboxylic acids, unsaturated cyclic tricarboxylic acids, saturatedcyclic tricarboxylic acids, hydroxy-substituted derivatives thereof, andthe like. It is appreciated that any such polycarboxylic acids may beoptionally substituted, such as with hydroxy, halo, alkyl, alkoxy, andthe like. In one variation, the polycarboxylic acid is the saturatedaliphatic tricarboxylic acid, citric acid. Other suitable polycarboxylicacids are contemplated to include, but are not limited to, aconiticacid, adipic acid, azelaic acid, butane tetracarboxylic acid dihydride,butane tricarboxylic acid, chlorendic acid, citraconic acid,dicyclopentadiene-maleic acid adducts, diethylenetriamine pentaaceticacid, adducts of dipentene and maleic acid, ethylenediamine tetraaceticacid (EDTA), fully maleated rosin, maleated tall-oil fatty acids,fumaric acid, glutaric acid, isophthalic acid, itaconic acid, maleatedrosin oxidized with potassium peroxide to alcohol then carboxylic acid,maleic acid, malic acid, mesaconic acid, biphenol A or bisphenol Freacted via the KOLBE-Schmidt reaction with carbon dioxide to introduce3-4 carboxyl groups, oxalic acid, phthalic acid, sebacic acid, succinicacid, tartaric acid, terephthalic acid, tetrabromophthalic acid,tetrachlorophthalic acid, tetrahydrophthalic acid, trimellitic acid,trimesic acid, and the like, and anhydrides, and combinations thereof

Illustratively, a polymeric polycarboxylic acid may be an acid, forexample, polyacrylic acid, polymethacrylic acid, polymaleic acid, andlike polymeric polycarboxylic acids, copolymers thereof, anhydridesthereof, and mixtures thereof Examples of commercially availablepolyacrylic acids include AQUASET-529 (Rohm & Haas, Philadelphia, Pa.,USA), CRITERION 2000 (Kemira, Helsinki, Finland, Europe), NF1 (H. B.Fuller, St. Paul, Minn., USA), and SOKALAN (BASF, Ludwigshafen, Germany,Europe). With respect to SOKALAN, this is a water-soluble polyacryliccopolymer of acrylic acid and maleic acid, having a molecular weight ofapproximately 4000. AQUASET-529 is a composition containing polyacrylicacid cross-linked with glycerol, also containing sodium hypophosphite asa catalyst. CRITERION 2000 is an acidic solution of a partial salt ofpolyacrylic acid, having a molecular weight of approximately 2000. Withrespect to NF1, this is a copolymer containing carboxylic acidfunctionality and hydroxy functionality, as well as units with neitherfunctionality; NF1 also contains chain transfer agents, such as sodiumhypophosphite or organophosphate catalysts.

With respect to the mixture of carbohydrates in the binder describedherein, it may include a mixture of two or more reducing sugars. In oneaspect, any carbohydrate in said mixture should be sufficientlynonvolatile to maximize its ability to remain available for reactionwith the acid precursor derivable from an inorganic salt and/or thepolycarboxylic acid ammonium salt. The carbohydrate mixture may includea monosaccharide in its aldose or ketose form, including a triose, atetrose, a pentose, a hexose, or a heptose; or a polysaccharide; orcombinations thereof A carbohydrate may be a reducing sugar, or one thatyields one or more reducing sugars in situ under thermal curingconditions. For example, when a triose serves as the carbohydrate incombination with other reducing sugars and/or a polysaccharide, analdotriose sugar or a ketotriose sugar may be utilized, such asglyceraldehyde and dihydroxyacetone, respectively. When a tetrose servesas the carbohydrate in combination with other reducing sugars and/or apolysaccharide, aldotetrose sugars, such as erythrose and threose; andketotetrose sugars, such as erythrulose, may be utilized. When a pentoseserves as the carbohydrate in combination with other reducing sugarsand/or a polysaccharide, aldopentose sugars, such as ribose, arabinose,xylose, and lyxose; and ketopentose sugars, such as ribulose, arabulose,xylulose, and lyxulose, may be utilized. When a hexose serves as thecarbohydrate in combination with other reducing sugars and/or apolysaccharide, aldohexose sugars, such as glucose (i.e., dextrose),mannose, galactose, allose, altrose, talose, gulose, and idose; andketohexose sugars, such as fructose, psicose, sorbose and tagatose, maybe utilized. When a heptose serves as the carbohydrate reactant incombination with other reducing sugars and/or a polysaccharide, aketoheptose sugar such as sedoheptulose may be utilized.

One or more aldotriose sugars may be used in combination with one ormore ketotriose sugars. One or more aldotetrose sugars may be used incombination with one or more ketotetrose sugars. One or more aldopentosesugars may be used in combination with one or more ketopentose sugars.One or more aldohexose sugars may be used in combination with one ormore ketohexose sugars.

One or more aldotriose sugars may be used in combination with one ormore ketotetrose sugars. One or more aldopentose sugars may be used incombination with one or more ketohexose sugars. One or more aldohexosesugars may be used in combination with one or more ketopentose sugars.One or more ketohexose sugars may be used in combination with one ormore aldotetrose sugars. And so on and so forth.

Other stereoisomers of such carbohydrates not known to occur naturallyare also contemplated to be useful in preparing the binder compositionsas described herein. When a polysaccharide serves as a carbohydrate incombination with monosaccharides, sucrose, lactose, maltose, starch, andcellulose may be utilized.

Furthermore, the mixture of carbohydrates in the binder described hereinmay be used in combination with one or more non-carbohydrate polyhydroxyreactant. Examples of non-carbohydrate polyhydroxy reactants which canbe used in combination with a mixture of carbohydrates include, but arenot limited to, trimethylolpropane, glycerol, pentaerythritol, polyvinylalcohol, partially hydrolyzed polyvinyl acetate, fully hydrolyzedpolyvinyl acetate, and mixtures thereof In one aspect, thenon-carbohydrate polyhydroxy reactant is sufficiently nonvolatile tomaximize its ability to remain available for reaction with the acidprecursor derivable from an inorganic acid and/or with a monomeric orpolymeric polycarboxylic acid ammonium salt. It is appreciated that thehydrophobicity of the non-carbohydrate polyhydroxy reactant may be afactor in determining the physical properties of a binder prepared asdescribed herein.

Commercial quality high fructose corn syrup, HFCS 42, which contains 42%fructose, may be used as the mixture of carbohydrates for the bindersdescribed herein. In one illustrative embodiment, the binder describedherein may be derived essentially from HFCS and an inorganic ammoniumsalt in aqueous solution. In another illustrative embodiment, the binderdescribed herein may alternatively or also comprise an ammonium salt ofa polycarboxylic acid, particularly a dicarboxylic acid or tricarboxylicacid, preferably citric acid.

Binders which comprise or consist essentially of the componentsdescribed herein may include additives, for example, additives selectedfrom: silanes, mineral oils, coupling agents, silicones or siloxanes(particularly for water repellency), silicon containing compounds,surfactants, hydrophilic additives, hydrophobic additives, waxes,substances useful for controlling the pH (e.g. ammonium hydroxide) andammonia. Ammonium hydroxide when used, and indeed other additives, mayprovide the and/or an additional source of nitrogen. Preferably, thetotal quantity of additives (excluding ammonia) is less than 5% byweight (excluding the weight of water present), more preferably lessthan 3% or less than 2% by weight. Particularly for mineral fiberproducts, it is preferred to include a silane as an additive. The binderand/or binder solution may comprise at least 0.1% and/or less than 1% ofa silane by dry weight. The silane may be amino substituted; it may be asilyl ether and it is believed that its presence may significantlyimprove the long term strength of the binder, particularly afterweathering.

Preferences for the pH of the binder are: preferred, pH≥7; morepreferred, pH≥8; and most preferred, pH≥9, at least in the state inwhich the binder is applied to a material to be bound and/or recoveredin a waste water recuperation system. Such a neutral or alkaline pH ofthe binder may alleviate problems of corrosion of manufacturingequipment which have been encountered with some essentially acidic priorart binder systems. Such prior art binders include binders consistingessentially of polyacrylic acids or polymeric polycarboxylic acids. Oneparticular advantage of the present invention is thus the use of abinder system that can operate in such neutral or alkaline conditions.When cured, the binder may become acidic during the curing process.However, equipment corrosion considerations are less significant in thiscase due to the minimal contact between the manufacturing equipment andthe binder when in this state. The pH of the binder may be less than orequal to 13, preferably less than or equal to 12, 11 or 10. A preferredpH may be in the range of 7.5 to 9.5, particularly 8 to 9. Binder whichhas been applied to the material to be bound and is subsequentlydissolved in water may have a pH of greater than 6.

It is preferred to arrange the pH of the binder solution at anappropriate level to prevent precipitation of its constituents andparticularly to ensure that the acid precursor derivable from aninorganic salt remains in solution. This is particularly the case whereammonium phosphate provides the acid precursor. Better dry and/orweathered strengths and/or more homogeneous products may be achieved byusing homogeneous binder solutions comprising ammonium salt acidprecursors which are free from precipitates, particularly when ammoniumphosphate is used and the binder solution is free from phosphateprecipitates.

The binder composition may be provided in the form of an aqueoussolution; it may contain free ammonia or excess ammonia in solution. Aneutral or alkaline pH of the binder may be generated by an excess ofalkaline groups compared with acid groups present in the bindersolution, for example, due partially or substantially to the presence ofammonia in the solution. Additional ammonia may be added to the bindersolution, for example 0.2%-1% by weight, or indeed more; this may helpto keep a wash water system alkaline over the long term, particularlyfor the manufacture of mineral wool insulation.

In the case or mineral wool fibers particularly for thermal insulationproducts, when binder solution is sprayed onto hot mineral wool fibersjust after they have been formed, the residual heat of the mineral woolfibers may cause a significant portion of any water in the bindersolution to evaporate. Consequently, the mineral wool fibers which arethen collected to form a bat may have binder present on them in the formof a sticky, viscous or tacky liquid. This may facilitate bondingbetween individual fibers via the binder.

One of the many advantages of this binder system is that it is applied,for example, by being sprayed onto mineral wool fibers, in asubstantially unreacted state. The ability to apply the binder solutionin a substantially unreacted state may alleviate problems associatedwith pre-reacting the binder components in solution which have beenencountered with some prior art binder systems in which the componentsare pre-reacted. Such prior art binders include binders consistingessentially of pre-reacted polymers or resins which are applied to thematerials to be bound. With substantially unreacted binder present inthe form of a sticky, viscous or tacky liquid on the material to bebound, the reaction between the binder components may occur in asubstantially dry state. One may describe the reaction as a bulkpolymerization because it is occurring without the benefit of a solvent.A particular advantage of the present invention is thus the use of abinder system that can polymerize in a substantially dry state orthrough a bulk polymerization.

Mineral fibers used in the context of the invention may be formed byinternal or external spinning. They may have a temperature in the range20° C. to 200° C., generally 30° C. to 100° C. or 150° C., when sprayedwith the binder solution. The quantity of binder solution sprayed may beused with or without additional water sprays to assist in cooling themineral fibers to a desired temperature between their formation andtheir collection to form a batt.

A particular advantage of using ammonia in solution to control the pH ofthe binder solution applied to the mineral fibers is that at least partof the ammonia of binder solution that sticks to the fibers may flashoff due to the residual heat of the mineral wool fibers. Consequently,the binder solution that coats the fibers may have a lower pH than thebinder solution sprayed.

The present invention extends to a method of manufacturing a mineralfiber thermal insulation product comprising the sequential steps of:forming mineral fibers from a molten mineral mixture; spraying asubstantially formaldehyde free binder solution on to the mineralfibers, the binder solution comprising: a mixture of carbohydrates(particularly a mixture of reducing sugars), an acid precursor derivablefrom an inorganic salt and/or an ammonium salt of a polycarboxylic acid,and a source of nitrogen; and collecting the mineral fibers to which thebinder solution has been applied to form a uncured batt of mineralfibers. Wash water may be sprayed on to mineral fibers between theirformation and their collection to form a bat, at least a part of thewash water having been sprayed on mineral fibers and subsequentlyreturned to a wash water system to be reused as wash water. The bindersolution may comprise wash water.

The binder may eventually be cured, for example in a curing oven; it mayform a thermoset binder. In its cured form, the binder may: comprisemelanoidins; and/or be thermoset; and/or be water insoluble orsubstantially water insoluble. The binder solution may be substantiallycolorless or white to off-white; upon curing, the binder may take on adark color, particularly a dark brown color. The cured product may bedark in color, particularly dark brown in color. The binder may be freeof proteins; it may be free of cellulosic feedstock. One of the manyadvantages of this binder system is that the extent of curing can bedetermined by the color. Substantially dehydrated binder appears whiteor off-white. Progressively cured to a greater extent, the binderappears progressively darker in color (a darker shade of brown). Whenapplied to mineral fibers, the extent to which the mineral woolinsulation has cured can be determined by its color.

When applied to the material to be bound and/or prior to curing, thebinder may be free or substantially free of melanoidins and/or otherreaction products derived from curing. Curing of the binder may produceglucosylamine, particularly as an intermediate product. Consequently, acured or particularly a partially cured product may compriseglucosylamine The reaction of the binder upon curing may be essentiallya Maillard type reaction as described for example in WO2007/14236. Thebinder may comprise polymerization products of a mixture that comprisesa mixture of reducing sugars and a material selected from the groupconsisting of ammonium sulfate, ammonium phosphate, ammonium nitrate andammonium carbonate.

The binder solution may be formulated by combining: a mixture ofreducing sugar carbohydrates (e.g., provided by HFCS), an acid precursorderivable from an inorganic salt (preferably an ammonium sulfate orammonium phosphate) and/or an ammonium salt of a polycarboxylic acid, asource of nitrogen, and water. The formulation may comprise optional oradditional ammonia provided in the form of an aqueous ammonia solution.The water may comprise wash water or recycled process water.

Forming the binder solution from a mixture of carbohydrates, an acidprecursor comprising an inorganic ammonium salt and/or an ammonium saltof a polycarboxylic acid provides one particular advantageouspreparation method. This may be achieved in a simple mixing chamberwhich may be open and/or at atmospheric pressure. The mixture ofcarbohydrates and the acid precursor and/or the ammonium salt may beadded in powder or liquid form. The preparation is preferably carriedout at room temperature. Preferably it is not necessary to supply heatto prepare the binder solution; nevertheless, the binder solution may beheated during its preparation, for example to a temperature with therange 20° C. to 80° C., particularly where this facilitates dissolvingand/or mixing of its ingredients.

The binder solution, particularly in the state applied to the materialto be bound, may comprise: at least 5% 10%, 15% or 18% solids and/orless than 70% or 60% (particularly in the case of wood boardapplications) or less than 50%, 40% or 20% solids (particularly in thecase of mineral fiber insulation applications) particularly determinedas bake out solids by weight after drying at 140° C. for 2 hours.

The collection of loose matter bound together by means of the bindersdescribed herein may comprise materials selected from: fibers, fibrousmaterials, mineral fibers, glass fibers, stone wool fibers, cellulosicfibers (including wood fibers, wood shavings, wood particles andsawdust), wood veneers, facings, wood facings, particles, woven ornon-woven materials, loosely assembled materials, woven or non-wovenmaterials.

The loose matter may be shaped and/or dimensioned and/or molded with theaid of the binder. The material produced may be selected from: a thermalinsulation material, a mineral fiber product, a wood board product(including chip board, orientated strand board, particle board, mediumdensity fiber board, wood facing products), foundry sands.

The matter to be bound may be at a temperature in the range 20° C. to100° C. when the binder is applied. The binder solution, particularlywhen applied to the loose matter, may have a viscosity appropriate forapplication by spraying or pouring. Its viscosity at 20° C. may be lessthan about 1.5 Pas, preferably less than about 1×10⁻² Pas, and/orgreater than about 2×10⁻⁴ Pas, preferably greater than about 5×10⁻⁴ Pas.

EXAMPLES

The following examples illustrate specific embodiments in furtherdetail. These examples are provided for illustrative purposes only andshould not be construed as limiting the invention or the inventiveconcept to any particular physical configuration in any way.

An uncured binder composition was prepared as HFCS 42:AmmoniumSulfate=76.4:16 based on dry solids. HFCS 42 is commercial quality HighFructose Corn Syrup with 42% Fructose concentration. The preferredmoisture content of an uncured fiberglass insulation product is 0.5% to4%.

Example 1: For a fiberglass insulation product with 7% LOI after cure,the free moisture content of the uncured fiberglass insulation productis in the range of 0.5% to 7%_(.)

Example 2: For a fiberglass insulation product with 15% LOI after cure,the free moisture content of the uncured fiberglass insulation productis in the range of 1% to 7%.

In order to demonstrate the supersaturated nature of acarbohydrate-based binder of the present invention, a preferred uncuredfiberglass insulation product from Example 2 has 5% free moisture.

The uncured fiberglass insulation product of Example 2 with an LOI of15% contains approximately 21.5% binder solids of HFCS 42:AmmoniumSulfate=76.4:16. This corresponds to 17.8% HFCS and 3.7% AmmoniumSulfate based on dry weight of uncured product. Said uncured product hasa free moisture concentration of 2.5%. The ratio of Ammonium Sulfate tofree moisture is 3.7:2.5. The ratio of HFCS 42:free moisture is 17.8:2.5At ambient temperatures (e.g., 20° C.) these ratios are beyond thesolubility ratios of HFCS:Water of approximately 17.8:7.7 andHFCS:Ammonium Sulfate=3.7:5.

Molding of 9-month-old uncured fiberglass insulation made with HFCS/AS(Cured binder LOI: 15-17%; Moisture of Uncured: 1.5%-3%; product storedin PE bag at 15° C.-24° C.) was associated with essentially nocrystallization, and the uncured insulation product was soft, showedgood recovery, and processed well. This is in contrast to Dextrose/ASmigrating and crystallizing out within 2 weeks, which illustrates aneconomic advantage of using HFCS.

What is claimed is:
 1. A composition comprising an uncured binderdisposed on mineral fibers, wherein the uncured binder consists of anaqueous mixture of (a) at least two reducing sugars comprising 1) atleast one aldohexose sugar selected from the group consisting ofdextrose, mannose, galactose, allose, altrose, talose, gulose, andidose; and 2) at least one ketohexose sugar selected from the groupconsisting of fructose, psicose, sorbose and tagatose, wherein themixture has a lower crystallization point than a carbohydrate mixtureconsisting of dextrose; and (b) an acid precursor derivable from aninorganic salt selected from the group consisting of ammonium sulfatesalts, ammonium phosphate salts, ammonium nitrate salts, ammoniumcarbonate salts and combinations thereof and/or (c) an ammonium salt ofa polycarboxylic acid; optionally (d) a silicon-containing compound; andoptionally (e) a corrosion inhibitor.
 2. The composition of claim 1,wherein the inorganic salt is selected from the group consisting ofammonium sulfate salts, ammonium phosphate salts, ammonium carbonatesalts, and combinations thereof.
 3. The composition of claim 1, whereinthe polycarboxylic acid is selected from the group consisting ofunsaturated aliphatic polycarboxylic acids, saturated aliphaticpolycarboxylic acids, aromatic polycarboxylic acids, unsaturated cyclicpolycarboxylic acids, saturated cyclic polycarboxylic acids, andcombinations thereof.
 4. The composition of claim 1, wherein thesilicon-containing compound is selected from the group consisting ofgamma-aminopropyltriethoxysilane, gamma-glycidoxypropyltrimethoxysilane,and mixtures thereof.
 5. The composition of claim 1, wherein thecorrosion inhibitor is capable of decreasing the corrosivity of thecomposition.
 6. The composition of claim 5, wherein the corrosioninhibitor is selected from the group consisting of dedusting oil,monoammonium phosphate, sodium metasilicate pentahydrate, and melamine.7. The composition of claim 1, wherein the composition is a fiberglassinsulation product.
 8. The composition of claim 1, wherein the mineralfibers comprise fibers selected from glass fibers and stone wool fibers.9. The composition of claim 8, wherein the mineral fibers comprise glassfibers.
 10. The composition of claim 1, wherein the mixture of at leasttwo reducing sugars is provided as high fructose corn syrup (HFCS). 11.The composition of claim 1, wherein the binder has a moisture content of1.5-3%.
 12. The composition of claim 1, wherein the binder has a pH of7.5-9.5.
 13. The composition of claim 1, wherein the mineral fiberscomprise glass fibers at a compositional concentration of 80-99% byweight.
 14. The composition of claim 1, wherein the binder compriscs has5-25% by dry weight of an acid precursor derivable from an inorganicsalt selected from the group consisting of ammonium sulfate salts,ammonium phosphate salts, ammonium nitrate salts, ammonium carbonatesalts and combinations thereof.
 15. The composition of claim 1, whereinthe binder has 10-20% by dry weight of an acid precursor derivable froman inorganic salt selected from the group consisting of ammonium sulfatesalts, ammonium phosphate salts, ammonium nitrate salts, ammoniumcarbonate salts and combinations thereof.
 16. The composition of claim1, wherein the aqueous mixture is a viscous or tacky liquid.